US4894645A - Incandescent matrix display with high frequency lamp driving - Google Patents

Incandescent matrix display with high frequency lamp driving Download PDF

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Publication number
US4894645A
US4894645A US07/199,527 US19952788A US4894645A US 4894645 A US4894645 A US 4894645A US 19952788 A US19952788 A US 19952788A US 4894645 A US4894645 A US 4894645A
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United States
Prior art keywords
bulbs
row
column
mains
unit
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Expired - Fee Related
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US07/199,527
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English (en)
Inventor
Lars B. G. Odlen
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PRISMA SKYLTREKLAM BOX 28001 S-200 28 MALMO A CORP OF SWEDEN AB
Prisma Skyltreklam AB
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Prisma Skyltreklam AB
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Assigned to PRISMA SKYLTREKLAM AB, BOX 28001 S-200 28 MALMO A CORP. OF SWEDEN reassignment PRISMA SKYLTREKLAM AB, BOX 28001 S-200 28 MALMO A CORP. OF SWEDEN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ODLEN, LARS
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/24—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using incandescent filaments

Definitions

  • the present invention relates to an electronic sign with a number of light bulbs provided in rows and columns (i.e., a matrix), whereby the light bulbs are turned on row by row or column by column (so called multiplex operation).
  • direct driving is used, which means that a coupling element is required for each lamp. Since an electronic sign may comprise many thousand bulbs, direct driving requires many thousand coupling elements and the gain is substantial if this amount of coupling elements can be spared. This is possible if the bulbs instead can be operated in groups (e.g., multiplex operation). Such operation in groups is utilized in connection with direct-current operation, which however causes problems with migration of material in the filaments of the light bulbs, which substantially reduces the life of said light bulbs.
  • the object of the present invention has been to eliminate said drawbacks and this is accomplished substantially by means of the characteristic features of claim 1.
  • the life of said light bulbs is substantially increased compared with direct-current operation while at the same time the advantages associated with direct-current operation are maintained.
  • FIG. 1 is a simplified block diagram over the alternating-current driving of the electronic sign
  • FIG. 2 is a more detailed block diagram over said alternating-current driving of the electronic sign
  • FIG. 3 is a block diagram illustrating synchronizing of row and column shifting at the alternating-current operation.
  • FIG. 4 is a block diagram illustrating current measurement at the alternating-current operation.
  • FIG. 1 is a block diagram for alternating-current (A.C.) operation of a multiplex light bulb matrix 1, while the A.C. operation occurs via diode and transistor matrix.
  • reference numeral 2 indicated incoming mains voltage (220 V, 50 Hz), 3 a switched mains unit (40 V, 8 A), 4 high-frequency A.C. current (>20 KHz), 5 a row driver (driver for eight rows of bulbs 6-13), 14 a column driver (driver for sixteen columns of bulbs 15-30), and 31 a synchronizing unit for generating synchronizing pulses 32 to a logic unit 33.
  • the switched mains unit 3 is connected to the logic unit 33 via a current meter 34 (this is shown in more detail in FIG. 4) and the logic unit 33 is connected 35 to a superior control unit 36, connected 37 to the row driver 5 and connected 38 to the column driver 14.
  • the mains voltage 2 is rectified and chopped up to 20-30 KHz by means of semi-conductor elements.
  • the high-frequency pulses thus obtained are fed to the primary winding in a ferrite transformer which also includes a secondary winding for power supply to the logic circuits.
  • the secondary side of the transformer generates high-frequency A.C. 4 with about 40 V, 8 A as maximum amplitude, and this A.C. is fed to the bulb matrix 1 via the row and column drivers.
  • the current of the secondary side is measured as the voltage drop across a resistor connected in series with the winding. These pulses of current are fed to a number of comparators on the logic unit 33.
  • the positive half-period of the secondary voltage generates synchronizing pulses to the logic unit (see FIG. 3).
  • the superior control unit 36 which preferably is a type of programmable unit (computer), send signals on an eight bit parallelous including information about which bulbs L in the bulb matrix 1 that should be lit in the sign.
  • the logic unit may present information of the number of defective bulbs L in each column 15-30 (see FIG. 4 and the corresponding text).
  • the members illustrated in the block diagram of FIG. 1 are shown in more detail.
  • the alternating voltage is fed from the transformer to the eight different column drivers.
  • the column drivers denoted COL 1-16 in FIG. 2
  • the voltage is divided into a negative and a positive component by means of the diodes D204 and D205.
  • the diodes D201 and D203, resistors R201 and R208 and transistors V201 and V202 generate the required operating current to the bases on V203 and V204 and are therefore not further explained here.
  • the other end of the column of bulbs, the common driving of rows towards earth, is taken care of by means of the sixteen row driver blocks, denoted ROW 1-16 in the figure.
  • the voltage is here also separated into a negative and a positive portion by means of the diode matrix D207-D238.
  • the diode matrix D207-D238 Along with the sixteen transistors V1-V16 and the thirtytwo diodes D1-D16, a full-wave bridge is defined, which can be short-circuited by the transistors and thereby earth the current.
  • the transistors V1-V16 and the surround resistors function as drivers for the base current to the transistors V1-V16 according to the above.
  • the row drivers ROW 1-16 are structurally more simple while they functionally are related to earth.
  • Control signals to the row drivers ROW 1-16 are obtained from the outputs of two SIPO shift registers, Z3 and Z4, which are fed from the logic unit 33. Low signal represents a lit bulb L.
  • the control signals for the column drivers COL 1-16 are obtained from the counter circuit Z1 via the buffer circuit Z2.
  • the counter Z1 is stepped for each new addressing latch pulse of the row driver shift registers Z3, Z4.
  • a resetting pulse is fed from the logic unit 33 to the counter Z1.
  • the counter Z1 is reset to activate the first column and the procedure can start from the beginning.
  • the row and column shifting of the logic unit is synchronized with the waveform of the switched mains unit.
  • connection 39 is intended to feed A.C. to the column driver 14.
  • the current from the transformer TR1 is measured in such a way that one pole of the transformer is connected to earth via a low-ohmic resistor 44 (see FIG. 4).
  • the voltage across this resistor 44 will then represent the current flowing through the winding of the transformer TR1. Since the current intensities are high, the power dissipation across the resistor 44 at full load will be substantial. Therefore, the resistor 44 is shunted by anti-parallel diodes 45 and 46, which connects the current via the morelow-ohmic resistor 47.
  • the diodes 45, 46 are silicon diodes which provide a shunt voltage of 0,6-0,8 V.
  • the diode 48 of shottky type has a less voltage drop and will conduct at voltages corresponding to the current intensity for a lit bulb L in the selected column.
  • the resistance net 49 and 50 voltage divides to the desired voltage, whereafter the signal is low-pass filtered in the condenser 51.
  • the circuits 52 and 53 are of open collector type and coupled as a window comparator.
  • the resistors 54, 55 and 56 feed the threshold voltages to the other inputs of the window comparator. High signal level will be present at the output of the comparator with the pull up resistor 57 only when the current in the transformer TR1 corresponds with the load of a bulb L.
  • connection 58 is intended to feed A.C. to the column driver 14 and the connection 59 to feed a signal if a bulb L is whole.
  • the superior control unit 36 By feeding out a test pattern, the superior control unit 36, the purpose of which is to generate the desired sign information, may in this way, via the logic unit 33 present in each sign module, get information about the working condition of the bulbs L and the sign electronics.
  • This information may be utilized to initiate change of bulbs and other maintenance work.
  • the bulbs L are thus operated with alternating current, whereby their life is substantially increased in comparison to direct current operation, since the migration of material appearing at direct current operation in always the same direction from one side of the filaments to the other and thereby the breakage of filament in a short time is eliminated.
  • the frequency of the A.C. preferably substantially exceeds the mains frequency and the A.C. is preferably obtained from a so-called switched mains unit 3.
  • the row and column driving preferably is controlled by a logic unit 33 and the shifting of said row and column driving from the logic unit 33 is preferably synchronized with the waveform of the A.C. from the switched mains unit 3.
  • the logic unit 33 preferably may feed to a superior control unit 36 a signal based upon measuring of A.C. from the switched mains unit 3 representing the working condition of various components, e.g. defective bulbs L.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Electroluminescent Light Sources (AREA)
  • Illuminated Signs And Luminous Advertising (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
US07/199,527 1987-06-03 1988-05-27 Incandescent matrix display with high frequency lamp driving Expired - Fee Related US4894645A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8702307 1987-06-03
SE8702307A SE454820B (sv) 1987-06-03 1987-06-03 Elektronisk ljusskylt med ett antal glodlampor anordnade i rader och kolumner

Publications (1)

Publication Number Publication Date
US4894645A true US4894645A (en) 1990-01-16

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Family Applications (1)

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US07/199,527 Expired - Fee Related US4894645A (en) 1987-06-03 1988-05-27 Incandescent matrix display with high frequency lamp driving

Country Status (3)

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US (1) US4894645A (de)
EP (1) EP0295478A3 (de)
SE (1) SE454820B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5068577A (en) * 1990-11-19 1991-11-26 Integrated Systems Engineering, Inc. Constant current drive system for fluorescent tubes
US5956003A (en) * 1996-07-24 1999-09-21 Hypres, Inc. Flat panel display with array of micromachined incandescent lamps
EP0827368B1 (de) * 1996-08-05 2001-05-30 Harness System Technologies Research, Ltd. Laststeuersystem

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19710855A1 (de) * 1997-03-15 1998-10-01 Dambach Werke Gmbh Leuchtdiodenmatrix-Anzeigevorrichtung

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4063234A (en) * 1975-08-08 1977-12-13 Arn Robert M Incandescent, flat screen, video display
US4283659A (en) * 1980-04-07 1981-08-11 The Singer Company Display system utilizing incandescent lamp multiplexing
US4488090A (en) * 1982-09-07 1984-12-11 Jack Hodson Advertising sign system
US4559480A (en) * 1982-11-15 1985-12-17 Omega Sa Color matrix display with discharge tube light emitting elements
US4688154A (en) * 1983-10-19 1987-08-18 Nilssen Ole K Track lighting system with plug-in adapters
US4745537A (en) * 1987-01-23 1988-05-17 Cheung P S Low dissipation power converter
US4771278A (en) * 1986-07-28 1988-09-13 Charles Pooley Modular large-size forming lamp matrix system
US4820956A (en) * 1987-10-02 1989-04-11 Integrated Systems Engineering, Inc. Light matrix display system

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3961365A (en) * 1974-10-24 1976-06-01 Stewart-Warner Corporation Color display device
US4262338A (en) * 1978-05-19 1981-04-14 Gaudio Jr John J Display system with two-level memory control for display units
US4323896A (en) * 1980-11-13 1982-04-06 Stewart-Warner Corporation High resolution video display system
FR2563643B1 (fr) * 1984-04-27 1986-08-14 Levionnais Philippe Dispositif de commande d'un tableau, ou mur lumineux a rangees d'ampoules electriques, ou similaires
DE3629884A1 (de) * 1986-09-02 1988-03-10 Mueller Tolk Eckhart Anzeigetafel mit aktiven displays im wechselspannungsbetrieb

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4063234A (en) * 1975-08-08 1977-12-13 Arn Robert M Incandescent, flat screen, video display
US4283659A (en) * 1980-04-07 1981-08-11 The Singer Company Display system utilizing incandescent lamp multiplexing
US4488090A (en) * 1982-09-07 1984-12-11 Jack Hodson Advertising sign system
US4559480A (en) * 1982-11-15 1985-12-17 Omega Sa Color matrix display with discharge tube light emitting elements
US4688154A (en) * 1983-10-19 1987-08-18 Nilssen Ole K Track lighting system with plug-in adapters
US4771278A (en) * 1986-07-28 1988-09-13 Charles Pooley Modular large-size forming lamp matrix system
US4745537A (en) * 1987-01-23 1988-05-17 Cheung P S Low dissipation power converter
US4820956A (en) * 1987-10-02 1989-04-11 Integrated Systems Engineering, Inc. Light matrix display system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5068577A (en) * 1990-11-19 1991-11-26 Integrated Systems Engineering, Inc. Constant current drive system for fluorescent tubes
US5956003A (en) * 1996-07-24 1999-09-21 Hypres, Inc. Flat panel display with array of micromachined incandescent lamps
EP0827368B1 (de) * 1996-08-05 2001-05-30 Harness System Technologies Research, Ltd. Laststeuersystem

Also Published As

Publication number Publication date
EP0295478A3 (de) 1989-12-27
EP0295478A2 (de) 1988-12-21
SE454820B (sv) 1988-05-30
SE8702307D0 (sv) 1987-06-03

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Owner name: PRISMA SKYLTREKLAM AB, BOX 28001 S-200 28 MALMO A

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ODLEN, LARS;REEL/FRAME:004919/0033

Effective date: 19880623

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Effective date: 19930116

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Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362